Purification and regeneration of waste lubricating oil based on electrostatic adsorption technology

At present, there are many processes for treating waste lubricating oil. The traditional sulfuric acid-white clay refining process is simple in method and low in cost, but consumes a large amount of sulfuric acid and white clay, and the generated waste residue will cause secondary pollution to the environment; distillation-hydrogenation process And short-distance distillation technology can greatly improve the quality of oil, but its processing conditions are high, equipment is complex, and the investment is large; the inorganic membrane method is applied to the regeneration of waste lubricating oil, which is easy to cause membrane pollution. Moreover, the separation performance is difficult to meet the processing requirements; the extraction-flocculation process can recover a large proportion of the base oil, but it requires a large amount of extraction solvent, and the solvent recovery after use is difficult; mechanical filtration The low precision and frequent replacement of the filter element increase the cost. The developing electrostatic adsorption technology has unique environmental advantages in the treatment of waste lubricating oil. It not only adsorbs solid mechanical impurities, but also has adsorption effects on impurities such as micro water, colloid and gas. The process has broad prospects for development.

The electrostatic generator is connected to the electrode to generate a high-voltage electrostatic field, so that the pollutants in the oil are polarized to display positive and negative electric properties respectively. By controlling the intensity of the high-voltage electrostatic field, the charged contaminants are opposite to each other under the action of the electric field. The direction moves, the neutral particles are squeezed and moved by the charged particle stream, and finally all the impurities, including solid particles, water, colloid and gas, are adsorbed on the adsorbent material, thereby achieving the purpose of high purification.

Electrostatic adsorption regeneration waste lubricating oil process

1. Pre-treatment of waste lubricating oil

The waste lubricating oil has a certain viscosity change after use, which will affect the subsequent processing. In order to reduce the processing difficulty and increase the processing speed during the treatment, the waste lubricating oil is heated in the early stage. The higher the viscosity, the slower the sedimentation rate. Appropriate heating can reduce the viscosity of the oil and increase the sedimentation speed. However, if the temperature is too high, it will cause oxidation of the oil. Therefore, the appropriate heating temperature should be selected in the early stage.

2. Treatment of waste lubricating oil moisture and mechanical impurities

Lubricating oil can invade moisture and produce mechanical impurities for various reasons during use. In the oil that invades moisture, oil quality deterioration occurs, and the performance of the lubricating oil is lowered. The simultaneous presence of mechanical impurities and moisture not only causes catalytic action in the oil, but also affects the subsequent electrostatic adsorption function. The moisture content of the waste lubricating oil of the electrostatic adsorption device is required to be 0.05% or less. Therefore, it is necessary to treat mechanical impurities and moisture in the early stage.

3. Waste lubricant treatment process

The waste lubricating oil in the waste lubricating oil tank is sent to the vacuum dewatering device ZK through the pre-filtration device YL through the feed pump B1, and the waste lubricating oil is dehydrated, and the vacuum degree is set to -0.08 MPa in the vacuum dewatering device. During this period, the waste lubricating oil is heated in two stages, the first heating temperature is 50 °C, and the secondary heating is 70 °C. It has been proved by research that this pressure and temperature will not affect the active ingredients of the oil in the waste lubricating oil, and the dewatering effect is obvious. The oily wastewater is finally collected and condensed and allowed to stand. The oil and water are collected in FY. After the condensation treatment, the oil moisture is 2 layers, the lower layer is water, the upper layer is oil, the middle hole is opened, and the water can be directly used as condensed water for recycling or flocculation treatment. After direct discharge, the upper layer of oil can be collected and processed again.

In order to improve the purification and regeneration effect, the electrostatic adsorption device is enhanced to capture small pollutants, and the adsorption capacity and dirt holding capacity of micro water, colloid and gas are exerted. It is sent to the filtering device through the discharge pump for parallel 3-stage filtration. The primary and secondary filtration is filtered by the bag filters DS1 and DS2. The filter screens are 300 mesh and 200 mesh respectively, which can filter the larger of the waste lubricating oil. The particulate impurities, the tertiary filtration is the electrostatic adsorption device JD. The processing time at each level is controlled by the EVB1, EVB2 and EVB3 motorized valves.

In order to improve the processing speed and effect of the subsequent electrostatic adsorption, the waste lubricating oil is subjected to a plurality of continuous circulation processes. After the pre-filter-vacuum dehydration-three-stage parallel filtration of the waste lubricating oil, the moisture content in the lubricating oil is reduced to 0. 05% or less, the larger dirt impurities are filtered, and the submicron in the oil after electrostatic adsorption The level of dirt impurities is adsorbed. The filter of the bag filter can be reused after backwashing; after the power is off on the adsorption plate, the debris falls off due to gravity, is discharged by the drain hole, and can be carefully cleaned after being opened by the quick connector. The treated oily residue can be treated in a harmless incineration process. The whole process adopts automatic control, and an automatic pressure alarm device is arranged on the processing device of each processing link. When the pressure difference is too large, the alarm can be automatically detected, indicating that the filter bag needs to be replaced or the electrostatic adsorption device needs to be drained.